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    <title>Document</title>
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    <script>
        /* 
        表达式：由数字、运算符、变量等组成的式子。
        有一个结果，结果成为返回值
        
        */
       let age =33+55;
       age + '艾克';
       age = age + '艾克';
       console.log(age);
    </script>
</body>
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